This invention relates to code templates and methods for use that are needed for the application, removal, and replacement of code markings and code blocks, which are used by automated guidance vehicles (AGV) that move about a floor of a factory, warehouse, or other facility by recognizing and following various types of guide paths, guide lines, and guide tracks. Such guide lines are usually used in conjunction with a wide variety of code markings and/or code blocks, which are encoded with various kinds of information such as positional location codes and synchronization codes that can be sensed and decoded by the AGV for purposes of maneuvering payloads while navigating through the facility. Such AGVs are also commonly referred to in the industry as autonomous guidance, automatic guidance, and automatically or autonomously guided vehicles.
Factories, warehouses, and other types of industrial and manufacturing facilities have seen an increased use of AGVs in daily operations. The AGVs are employed in a wide variety of duties and are capable of a wide range of autonomous and/or preprogrammed operations. The AGVs can serve in a wide range of duties including automatically moving products, parts, and people safely, efficiently, and quickly about the facility. Often, AGVs are presently used by inventory storage and order picking systems in warehouses, and by assembly-line manufacturers who require just-in-time delivery from one factory location to another of raw materials, parts, partially or completely assembled automotive components.
In most applications, AGVs move about the floor space of the factory, warehouse, airports, or other type of facility along pre-designated paths. The paths are designated and identifiable to the AGVs in a number of ways, which include, to name only a few, 1) preprogramming the paths or tracks into the AGV computer memory banks; 2) installation of trackways, railways, guide-wires, and other types of prepositioned cables, electrical, and electromechanical devices; 3) prepositioning of AGV recognizable targets; 4) prepositioning of magnetic, energizable, and energy emitting and reflective devices, including specially formulated paints, tapes, and other substances and materials that are applied to floor path and guide ways; and 5) various combinations of the preceding systems.
Ordinarily, the most cost effective systems employ a predesignated path way, guide path, or guide track, which includes a guide line that is applied to the floor surface along the predesignated path way or paths. The AGV is configured to recognize the guide line for purposes of achieving navigational control and accurate movement of the AGV""s payload, whether it be people moving across an airport or material moving quickly through an assembly line. Such guide lines can be employed either alone or in combination with any of the previously described systems. The guide lines or tracks are also typically used in conjunction with various types of code markings that are applied to the floor surface, proximate to or along the guide line. Such code markings or code blocks are usually encoded with specific information that can describe a location within the facility. Such code blocks can also serve as way points for various types of AGVs that may be employed and configured for different or cooperative functions. The AGV is usually configured to recognize the code blocks for purposes of speed control, location and way point identification, distance measurement, and for synchronization of on-board distance measuring and location identification devices.
AGVs and guide line marking systems have been in use for some time and are described in more detail in the prior art, which includes U.S. Pat. Nos. 3,935,922 to Cooper et al.; 4,003,445 to DeBruine; and 4,379,497 to Hainsworth et al.; which are all incorporated herein by reference in their entirety. Each of these references also specifically describes various types of guide line and code marking systems.
The code marking systems are recognized by AGV sensing systems that create signals used by on-board control systems. The control systems can thereby establish the AGV""s location in the facility, effect navigational control during transit of the AGV, as well as calibrate and synchronize other AGV parameters such as distance measurement sensors, payload disposition controllers, and directional control subsystems. Additional types of navigational control systems and guide line sensing devices configured for use with AGVs are described in U.S. Pat. Nos. 3,970,840 and 4,307,791, both to DeBruine.
Various types of materials have been used to apply code markings to floor surfaces. U.S. Pat. Nos. 4,707,297 to Paske, Jr. et al. and 5,277,839 to Schultz, which are incorporated herein by reference in their entirety, disclose a variety of compounds that may be useful for purposes of applying a guide line to a floor surface, and which are compatible for use with the previously described AGVs and for purposes of the present invention.
The prior art devices have demonstrated that the location of the guide tracks and lines and the precision location of various types of code markings and code blocks can significantly simplify the operation and improve the performance of AGVs during transit. The large majority of AGVs are configured to measure distances during transit in addition to being equipped to follow predesignated path lines or guide tracks that are applied to the floor surface. In most configurations, the AGVs measure the distance traveled in units of length. They also scan for the prepositioned guide line for purposes of remaining within the bounds of the predesignated path way during transit through the facility. In addition to scanning for the guide line, the AGVs are also configured to scan for various types of location and synchronization code markings. Such markings are often arranged in the form of a block of markings positioned on or proximate to the guide line. The location code markings are usually placed in positions, such as intersections on aisles and path ways in the facility, where various different AGVs may need to go in different directions that depend on the final destination of the AGV""s payload. Thus, those with skill in the art have come to appreciate that a code block that is misplaced even by a few inches or centimeters can adversely impact the proper operation of the AGVs. This effect is even more pronounced in large facilities such as airports, warehouses, and manufacturing operations where AGVs must transit accurately across large distances.
During routine transit through the facility, the AGV may need to recalibrate its distance measuring equipment because many such measuring systems experience decay in the accuracy of the distance measured over time. Thus, regular resynchronization is needed to minimize inaccuracies in the distance measuring equipment. The synchronization code markings are typically situated at many locations throughout the facility and proximate to the guide line. To minimize inaccuracy in measuring distance, the AGV scans for the prepositioned synchronization code markings or code block, which contains encoded distance measuring information, to recalibrate the onboard distance measuring systems. Such recalibration enables more accurate AGV speed control and distance measurements, which, in turn, prevents collisions and improves the overall accuracy and efficiency of AGV movement through the facility.
Some attempts have been made to improve the accuracy with which AGV users, such as facilities engineers, apply the code markings and code blocks to floor surfaces. Such attempts include use of a template configured with cut-outs that correspond to the various possible code markings. The template can be used to assist in precise placement of the location and synchronization code markings proximate to the guide line or track. However, the templates presently in use suffer from many shortcomings, which include, for example, the lack of any features that allow the efficient removal and accurate replacement of code markings that have become damaged or worn over time. Additionally, no device exists that can easily assist the user with determining the positional and informational accuracy of the various types of code markings before and after application to the floor surface.
As has often been experienced, the application, removal, and reapplication of code markings often results in improperly located code markings, or in the application of code markings that are incorrect, and which convey inaccurate location information. Improperly positioned code markings can cause the AGV to turn to soon or too late along the guide line, which can cause a collision and damage to a payload. Incorrectly applied code markings that contain improperly coded information can result in the AGV obtaining inaccurate location or synchronization information, which can result in a wide variety of operational errors.
In most cases, when an error condition is experienced, the AGV is preprogrammed to initiate an error mode that stops the vehicle, sounds off or sends an alert message, and discontinues autonomous operation until a user intervenes and corrects the error condition. The AGV error mode may prevent accidental collisions or unexpected travel along improper path ways. However, in a facility that has more than one AGV in operation, and some facilities may employ dozens of autonomously operating AGVs, if one AGV stops, then all other AGVs must also stop if they move along the same path way and/or follow the same guide line that has the inaccurate or improperly placed code markings or code block. This can result in an AGV traffic jam that can result in countless hours of lost production time, which, in turn, results in a significant loss of revenue and operating efficiency. For a facility such as an airport or automotive manufacturing assembly line factory, which usually operate around the clock, the delays and missed flight connections cannot be undone, and the lost production time can not be recovered.
None of the preceding references disclose or suggest the use of a code marking template that can prevent the type of placement and coding errors described above and that has the benefits of the present invention. What has been needed, but heretofore unavailable, is an improved, more efficient, and user friendly device and method for applying, removing, and replacing code markings and code blocks that are compatible for use with the many types of AGV code marking systems presently in use. As is known to those with skill in the art, and especially to those with experience in using AGVs in the harsh environments associated with the automotive, assembly-line manufacturing industry, the guide lines or tracks become damaged and worn over time because many users travel across the designated path ways and can damage the guide lines and code blocks with an undesirable but regular frequency. Thus, a reliable and accurate device is needed to minimize the time required to apply, remove, and replace the code markings needed by AGVs so that they can operate efficiently and without error.
Accurate placement and coding of AGV code markings can eliminate expensive production and operating delays. Moreover, routine maintenance of normal code marking wear and tear can be greatly simplified for the facilities engineer responsible for the application, removal, and replacement of code markings. A significant amount of time is required to initially preposition a code marking and code block in the proper location. Once it is accurately located and applied to the floor for the first time, a considerable amount of time must be expended to precisely measure the location of the code block so that the AGV(s) that must rely upon the code block can be precisely programmed with the exact distance to or from and location of the code block. As stated, this is required because most AGVs are configured to precisely measure the distance between the various code markings and code blocks. Once the code block location is established and preprogrammed into the AGV(s), removal and replacement, after wear and tear or damage has occurred, must be at the precise location as originally prepositioned. Any deviation from the original position requires a considerable amount of re-measuring of the code marking location and re-programming of the AGV(s). Any reduction in the likelihood of error during the code marking application process can have a positive impact on the bottom line of any facility that employs AGVs that use guide lines and code markings. This is especially true in the automotive assembly-line manufacturing operations where even the smallest delay in the xe2x80x9cjustin-timexe2x80x9d manufacturing processes can result in an unexpectedly large increase in costs and a major decrease in operational efficiency.
The AGV guide path code templates and methods for use of the present invention offer a solution to the problem of improper code marking placement and the problem of applying code markings that are encoded with incorrect information. The novel and inventive solution accomplishes this with a simple and efficient device and method for use that demonstrates a significant improvement when compared with previous devices and methods, and which more readily meets the requirement for precisely located and properly coded code markings, which are needed for proper and error-free operation of AGVs.
In general, the present invention relates to automated guidance vehicle (AGV) guide path code templates and methods for use for improved application, removal, and replacement of AGV guide line code markings, which are otherwise referred to as code blocks. The automated guidance vehicle code template for creating location code markings or code blocks according to the present invention includes a generally planar template substrate that is formed with control and alignment aperture patterns that are correspondingly offset from each other. The control and alignment patterns are formed with a plurality of spaced-apart code spur openings wherein each of the openings of the control aperture pattern corresponds with an offset opening of the alignment aperture pattern. In both patterns, each opening represents either a synchronization, start, finish, on, or off bit that is contained in the guide line code marking.
The code template further includes a series of indicia that corresponds to each of the code spur openings and which is representative of a control spur bit identifier. For example, a typical code marking block may include as few as 4 or as many as 10 bits. In either configuration, a start bit and a finishing bit are, in most cases, included in the code marking. The respective, remaining 2 to 10 bits represent binary code digits that in turn represent a base two exponent and a base 10 number. If 2 bits are used, then each binary digit corresponds to a base two exponent between 0 and 1, which, in turn, corresponds to a base 10 number between 1 and 2. For example, 20=1 and 21=2. If 10 bits are used, with a start and a finish bit that leaves 8 bits for numeral representation, then each binary digit corresponds to a base two exponent between 0 and 7, and a base 10 number between 1 and 128. The indicia identify the bit as either a start, finish, or digit identifier bit. Additional indicia may be included as described in more detail below in connection with the various figures.
In a variation of the preceding embodiment, the automated guidance vehicle code template is preferably formed with the plurality of code spur openings wherein each pattern includes at least a start framing bit opening and a finish framing bit opening. More preferably, the code template is formed with the plurality of code spur openings of each pattern including start and finish framing bit openings and at least 2 on bit and 2 off bit code spur openings. Even more preferably, the code spur openings of each pattern includes start and finish framing bit openings and at least 8 on bit and 8 off bit code spur openings.
The present invention also contemplates an automated guidance vehicle code template for creating synchronization code markings. This variation of the present invention further includes a generally planar template substrate that has control and alignment aperture patterns formed therein that are correspondingly offset from each other. A plurality of spaced-apart code spur openings forms the control and alignment aperture patterns wherein each of the openings of the control aperture pattern corresponds with an offset opening of the alignment aperture pattern and represents either a synchronization (hereafter xe2x80x9csyncxe2x80x9d) on or sync off bit. This variation further preferably includes a series of indicia corresponding to each of the code spur openings and that is representative of a control spur bit identifier.
A kit of automated guidance vehicle code templates for creating synchronization and location code markings is also described according to the principles of the present invention, The kit includes a plurality of generally planar code templates each having control and alignment aperture patterns that are correspondingly offset from each other and that are formed in the templates. A plurality of spaced-apart code spur openings form the control and alignment aperture patterns. Each of the code spur openings of the control aperture pattern corresponds with an offset opening of the alignment aperture pattern and represents either a start, finish, on, off, sync on, or sync off bit. Each of the code templates in the kit further includes a series of indicia corresponding to each of the code spur openings and that represents a control spur bit identifier. Preferably, the kit includes code templates wherein the plurality of code spur openings of each pattern includes at least a start framing bit opening and a finish framing bit opening. More preferably, the kit of code templates is configured wherein the plurality of code spur openings of each pattern includes start and finish framing bit openings and at least 2 on bit and 2 off bit code spur openings. Even more preferably, the kit of code templates is arranged wherein the plurality of code spur openings of each pattern includes start and finish framing bit openings and at least 8 on bit and 8 off bit code spur openings.
In a variation of the kit form of the instant invention, each of the plurality of code spur openings forming the control pattern corresponds with an opening of the alignment aperture pattern and represents either a sync on or sync off bit. More preferably, each of the plurality of code spur openings forming the control pattern corresponds with an offset opening of the alignment aperture pattern and represents either a sync on or sync off bit; and the plurality of spaced-apart code spur openings also includes start and finish framing bit openings and at least 2 on bit and 2 off bit code spur openings. Most preferably, the kit of this variation is adapted wherein the plurality of code spur openings forming the control pattern corresponds with an offset opening of the alignment aperture pattern and represents either a sync on or sync off bit; and wherein the plurality of code spur openings includes start and finish framing bit openings and at least 8 on bit and 8 off bit code spur openings.
The present invention is also directed to a method for removing and replacing automated guidance vehicle code markings using a code template for creating location code markings. The method includes the steps of:
a. identifying an original code marking that has become damaged or worn;
b. selecting a code template that includes a generally planar template substrate having control and alignment aperture patterns formed in the template and correspondingly offset from each other and a plurality of spaced-apart code spur openings forming the control and alignment aperture patterns wherein each of the openings of the control aperture pattern corresponds with an offset opening of the alignment aperture pattern and represents either a sync on, sync off, start, finish, on, or off bit;
c. placing the code template over the damaged or worn code marking and aligning the control aperture pattern with the code marking to be removed and replaced;
d. temporarily marking the code spurs in the alignment pattern with offset traces that correspond to the code spurs of the original code marking;
e. removing the code template from the original code marking area;
f. preserving the offset code spur traces that were marked using the alignment aperture pattern;
g. removing the damaged or worn code marking spurs;
h. placing and positioning the code template to align the alignment aperture pattern with the preserved code spur traces;
i. marking the code spurs in the control aperture pattern corresponding to the preserved code spurs in the alignment aperture pattern; and
j. applying replacement code spurs.
In a variation of the preceding method, the method further includes the steps of identifying and annotating the information represented by the damaged or worn code spurs before removal and verifying the accuracy of the information represented by the code spurs marked in the alignment aperture pattern before the replacement code spurs are applied to the floor, wall, or other target. Another variation includes the step of preparing the floor, wall, or other target surface where the damaged or worn code spurs were removed before applying the replacement code spurs. The step of removing the temporarily marked code spurs after application of the replacement code spurs is also contemplated by the method of the present invention. The present invention is also directed to a method that includes a step wherein a sealer is applied to the replacement code spurs to improve resistance of the code spurs to damage and wear.